Cassettes for test tubes are widely used in many applications such as fraction collectors. A fraction collector is used for dispensing a flow of liquid into a number of receptacles, such as test tubes. Normally the test receptacles are fed towards a dispensing means by means of a relative movement in one or two directions. As the droplets dispensed can have a diameter of 4 millimeters and the smallest tubes have an orifice of 6.7 millimeter it is important that the tubes are held in exactly the right position to avoid spilling. To allow for different tube manufacturers and account for the tolerances in their production the tubes are normally spring loaded which is also an advantage when emptying all test tubes of waste fluid after use.
However, the spring load introduces a force which the user has to overcome when loading the cassettes and after emptying the cassette of waste fluid the empty tubes are normally put in another container for further processing. Since the tubes are vertically fixed this has to be made manually test tube by test tube which is very cumbersome and annoying. Thus there is a need for a cassette in which the test tubes are normally held in a fixed position vertically and horizontally but where the test tubes can also easily be released when loading the cassette and emptying the cassette of test tubes.